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| Author(s): |
Carmen Cecilia Sicherle
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Botucatu. 2016-09-28. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária e Zootecnia. Botucatu |
| Defense date: | 2016-08-03 |
| Advisor: | Maria Denise Lopes |
| Abstract | |
The aims of the study were to assess individual characteristics and sperm concentration of cryopreserved semen characteristics using different structural and functional analysis and dog fertility. Twenty ejaculates were collected from 5 dogs and sperm were cryopreserved by one-step protocol. To better understand dog semen quality after thawing five healthy mature dogs were used to the one-step sperm cryopreservation protocol. Sperm analysis was performed at three time points: after collection, refrigeration, and after thawing, by computer sperm motility analysis (total [TM] and progressive motility [PM], and rapid sperm), membrane damage (membrane fluidity and viability - Yo-Pro 1 and merocianina 540, phosphatidyl serine translocation – annexin – V – propidium iodide - PI, acrosomal and membrane integrity FITC-PSA – PI), mitochondrial potential (JC-1), membrane lipid peroxidation, LPO (BODIPY 581/591 C11) and apoptosis (kit CellEventTM Caspase-3/7- FITC Green Flow Cytometry), evaluated by flow cytometry. Twenty bitches were inseminated by transcervical intrauterine (TCAI), twice using 2 sperm concentration (160 and 450 x 106 spermatozoa/TCAI). A decrease on frozen/thawed semen comparing to fresh and cooled semen occurred for the parameters of total and progressive motility (TM 87.00 ± 1.24, 88.15 ± 1.38, 72.55 ± 6.26; PM 69.95 ± 1.28, 71.75 ± 1.91, 56.30 ± 6.00, fresh cooled and frozen/thawed respectively P < 0.01), percentage of rapids (83.15 ± 1.94, 81.55 ± 1.53, 64.30 ± 7.68 P < 0.01), membrane fluidity and cell viability (78.29 ± 6.22, 75.76 ± 6.60, 23.02 ± 9.12 P < 0.01) and acrosomal and membrane integrity (85.71 ± 6.22, 70.37 ± 6.43, 30.87 ± 9.90 P < 0.01). Sperm cells were affect for cooling and freezing process when analyzed for the translocation of phosphatidyl serine (79.90 ± 7.95, 63.50 ± 4.66, 27.19 ± 9.22 P < 0.01) and high mitochondrial potential (85.15 ± 2.76, 60.52 ± 3.31, 38.06 ± 6.40 P < 0.01). For LPO significant difference was observed in semen after thawing only comparing to cooled semen (16.57 ± 5.44, 16.22 ± 2.43, 23.00 ± 4.13 P < 0.05). No difference on caspase activity was observed. Dog 1 was significantly better for the parameters of plasma membrane and acrosome integrity and mitochondrial potential. By calculating the average of the animal response and minimum and maximum limits, although there is no difference, we observed that the semen from Dog 1 displayed better post thaw values for all analyzes. The pregnancy rate was 0% for dog 1 and 50% for pool at concentration 450 x 106 spermatozoa. In conclusion, cryopreservation leads to structural and functional changes in sperm cell, which explains their short survival after thawing. The cryo-capacitation like changes can be related to others factors, as the seminal plasma proteins that are not know yet on this species. Apoptosis process can be initiated with the opening of mitochondrial pores during the freezing/thaw process, which releases pro-apoptotic factor on the cytoplasm. The mitochondrial potential is not related to sperm motility but sperm survival. Although the dog 1 displayed better sperm quality, no pregnancy was observed, which makes us to rethink the prediction of fertility of semen samples by commonly used parameters. The concentration dose used for AI procedures must consider motility and sperm viability to satisfactory pregnancy rates. (AU) | |
| FAPESP's process: | 13/02050-5 - Sperm subpopulations evaluations on dogs ejaculate aiming fertility and cryopreservation analysis |
| Grantee: | Carmen Cecilia Sicherle |
| Support Opportunities: | Scholarships in Brazil - Doctorate |